The subject of this invention is a delivery device for the delivery of fluid into two mutually independent nozzles using a feed pump, and having a valve connecting the feed pump optionally with a first or a second nozzle, and having sealing devices and retaining mechanisms for a sealed connection between the valve and the feed pump.
Delivery devices of this type, for example, are often used to deliver washing fluid in windshield washer systems for motor vehicles, and their practical applications are well known. The feed pump of the known delivery device can be driven in its two rotational directions, and has one intake and two outlets. Depending on the rotational direction of the feed pump, at one of the outlets overpressure is being generated while at the other one underpressure is being generated. This overpressure and underpressure moves a membrane in the valve, so that the outlet with the overpressure is connected to the designated nozzle. For their connection, the feed pump and the valve are equipped with side by side pairs of interlocking nozzles with an O-Ring forced in between each. The O-rings seal the nozzles against each other, and fasten the valve to the feed pump.
The disadvantage of the known device is its use of O-rings, which are very expensive and difficult to install. The high number of O-rings required for just one delivery device makes its manufacture very expensive.
The objective of this invention is to improve a delivery device of the aforementioned type to such extent that its manufacture becomes very economical.
The invention solves the problem by placing the sealing devices and the retaining mechanisms apart from each other.
This design avoids the joint placement of the sealing devices and the retaining mechanisms in the area where the feed pump connects to the valve. This allows for an especially simple design for the sealing devices and retaining mechanisms without the use of expensive O-rings and makes the delivery device introduced by this invention especially economical.
In an advanced design, the retaining mechanisms are especially simple when a locking device is employed.
In another advanced design, the sealing devices can be easily designed for a specific sealing pressure if the retaining mechanisms are designed to provide the initial tension for the sealing devices.
An additional advanced design of the invention using a small number of retaining mechanisms provides a simple solution to prevent the valve from tilting relative to the feed pump by locating the retaining mechanisms between two pairs of interconnected nozzles of the feed pump and valve. In the simplest case, the design of the delivery device described in this invention requires only one retaining mechanism.
Proper sealing between valve and feed pump is reliably guaranteed as the result of a further advanced design, if the nozzles of the feed pump and the valve are designed to interlock conically.
With the valve pre-lightened relative to the feed pump, the seal (even in the presence of high pressures) is especially reliable, if at least one of the nozzles has circumferentially extending sealing beads. Along the sealing beads, the nozzles exhibit especially high surface pressure.
In a further advanced design, the locking device can be designed especially easily, if the locking device is comprised of interlocking latching hooks.
In another design step, the valve is reliably connected to the feed pump, if the locking device extends nearly across the entire area between the nozzles.
In another advanced design, the nozzles of the feedpump have two areas each designed as fixed fitting and as sealing fitting.
It has been proven to be especially advantageous for the sealing fitting to be installed at the end of the pump nozzle while the fixed fitting is located closer to the feed pump. Both surfaces can be designed as beads, which fit into matching recesses in the valve nozzles.